OLD BONES BY THE NUMBERS

The East Village construction site for the new Thomas Jefferson School of Law has become the dig of dreams for San Diego paleontologists.

Yesterday, the jaw, shoulder blade, neck bone and upper spine of a baleen whale, possibly 600,000 years old, were found in the reddish soil where excavation is taking place for the $68 million project. The ocean-going creature might have been 40 feet long.

On Feb. 3, in the same southeast corner of the construction zone and about 10 feet above yesterday's find, the skull, two tusks, foot and leg bones of a Columbian mammoth were discovered.

That animal was estimated to be about 500,000 years old and was the largest land animal of its time, possibly standing 15 to 17 feet tall.

It is rare to find such large fossils of land and sea in such close proximity, said Thomas Deméré, curator of paleontology at the San Diego Natural History Museum.

“It's unprecedented in San Diego County,” Deméré said.

He said the whale is the first of its geological age found in the county and only the second found in Southern California. He said little is known about whales from the Pleistocene Epoch – ranging from about 1.8 million years ago to about 10,000 years ago – because there are no rocks that preserve their remains.

“Hopefully, it will tell us more about the evolutionary history of these animals,” Deméré said.

The whale bones were scattered over an area about 40 feet wide, apparently moved by bay currents, said Pat Sena, a field paleontologist with the museum.

Sena discovered the mammoth and whale fossils. He had recently uncovered horse fossils and was expecting he might find another mammoth when the whale bones poked out of the dirt.

“I was astonished,” Sena said. “You don't see that very often – so I was excited.”

Sena said whale fossils dating back about 3 million years have been found at construction sites in National City and Chula Vista.

The discoveries of the mammoth and the whale, separated by about a one-story layer of soil, reveal the ebb and flow of global weather in ages past.

“When sea levels are in, it's a warmer climate – polar ice caps are melting and sea levels are rising,” Sena said. “We're looking at periods of global warming and global cooling in a real short package of time here.”

Gray whales, humpback whales, blue whales and bowhead whales are modern-day relatives of the baleen whale found yesterday. The term baleen refers to a broad suborder of whales that have no teeth but filter and swallow their prey. Paleontologists at the scene said additional study would show what variety of baleen whale perished in what is now the East Village.

“What we need to figure out is, who does that jaw belong to – what family of whales,” said Sarah Siren, another museum paleontologist.

Thomas Jefferson School of Law Dean Rudy Hasl carried a cardboard box from the dig site with several pieces of whale bone.

“These are pieces of bone that have been impregnated with the minerals from the soil,” he said. “These were down there a long, long time.”

Previously discovered scallop shells, which are neatly preserved and have a bronze hue, will be imbedded in the floor of the law school's foyer, Hasl said.

“People will be walking on 500,000 years of history,” he said.

The paleontologists are carefully removing the bones using hand axes, shovels, trowels and brushes. The last of the mammoth's bones were moved from the site last week, and the excavation of the whale may not be completed until next week.

Both ancient mammals will be studied by the Balboa Park museum's experts and eventually put on display.

Construction crews must still dig down 10 more feet for the law school's foundation. Might more remains of Ice Age animals be unearthed?

“The way it's going? Yeah,” Sena said. “They just keep popping out of the ground.”